The subject invention concerns an arrangement in doors of the kind comprising at least one door leaf of a first material, which door leaf is provided with an insert of a second material having properties differing from those of the first material. Both the first and the second materials are sufficiently flexible to allow the door to be closed by the door leaf being respectively wound-on and wound-off.
In doors of this kind it is often desirable that the insert of the second material, which is attached to the first material, is in the form of a window through which it is possible to ascertain the presence on the other side of the door of objects, such as a vehicle, or of a person. Such transparent materials are, however, less durable when exposed to mechanical wear than is the material making up the rest of the door leaf. The less durability of such transparent materials is a consequence of the inherent tendency of such materials to crack when exposed to temperature variations. Furthermore, after a period of service the transparent material generally is scratched to such a degree that its see-through properties are almost entirely lost and consequently the transparent window material needs to be replaced. However, to replace the transparent material requires considerable work as the seam must be ripped up and a new piece of material be sewn on. As a rule, this operation requires that the entire door leaf be dismounted.
In some cases it may be advantageous to replace one window possessing certain properties by another window having different properties. For instance, it may be desirable to install windows of tight transparent materials during the winter season while in the summer the use of a transparent material with vent holes therein may be more desirable.